Multiple type absorption air conditioning system

ABSTRACT

The capacity control range of an interior unit of a multiple type absorption air conditioning system is enlarged, and turning on and off of cooling/heating and switch over between the cooling and heating can be readily and safely performed. The capacity control range is increased by reserving a liquid refrigerant in an absorption cool/warm water unit. An interior unit is connected to the absorption cool/warm water unit by a communication device. The operation of the cool/warm water unit caused by turning on and off the system and switch over between cooling and heating are automatically controlled by an operation control device. Consequently, the operation is simplified, and safety is improved.

This is a continuation of application Ser. No. 859,989, filed Mar. 30,1992, now U.S. Pat. No. 5,282,369.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an air conditioning system whichemploys an absorption type cool/warm water unit, and more particularly,to a multiple type absorption air conditioning system which can bereadily switched over from the cooling operation to the heatingoperation, and reversely in accordance with individual air conditioningrequirement.

2. Description of the Related Art

Japanese Patent Unexamined Publication No. 60-263058 discloses theabsorption type cool/warm water unit which can be switched over from thecooling operation to the heating operation, and reversely. Aconventional air conditioning system employing such an absorption typecool/warm water unit has a disadvantage in that it requires separateoperations of the air conditioners installed in individual rooms in abuilding and the absorption type cool/warm water unit, which is anoutdoor unit. Further the air conditioners and the absorption typecool/warm water unit must be switched on respectively when an airconditioning is desired. Consequently, even when a user in one of therooms desire an air conditioning and switches on the air conditioner inthat room, the room cannot be air conditioned unless the absorption typecool/warm water unit is switched on. Another drawback of theaforementioned conventional air conditioning system is that the airconditioner and the absorption type unit must be operated along thepredetermined operation procedures in order to eliminate troubles, suchas crystallization of a solution. That is, when the absorption typecool/warm air unit is to be activated for cooling, starting-up of thecooling operation must be postponed until a difference in theconcentrations of the solutions is generated. Also, when the absorptiontype cool/warm air unit is to be stopped, stoppage of the operationthereof must be postponed until the concentrated solution is diluted inorder to prevent the solution from being crystallized due to cooling bynatural heat radiation. If the cool/warm water unit is activated orstopped in a state in which no heat load is applied thereto from an airconditioner or a fan coil unit, the solution crystallization ordisability of the diluting operation may occur hence, regardless of therequest of a load, part or all of the air conditioners or fan coil unitsmust be operated to circulate the cool/warm water before the absorptiontype cool/warm water unit is operated. However, this operation is socomplicated that the ordinary user cannot do that. Furthermore, switchover of the cooling and the heating operations requires switching overof the operations of the absorption type cool/warm water unit. That is,switch over of the cooling/heating operations requires switching over ofthe refrigerant cycle and draining of a cooling water from an absorberand a heat exchanger of a condenser, which cannot be done by theordinary user as well. Furthermore, since part or all of the airconditioners or fan coil units are operated to circulate the cool/warmwater before the operation of the absorption type cool/warm water unitis started regardless of the request of the load, energy is wasted interms of the ventilation activating power and cool/warm watercirculating power.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a multiple typeabsorption air conditioning system which can be easily operated for airconditioning in order to meet the request of air conditioning or ofswitch over between the cooling and heating which are made by the usersfrom a plurality of rooms.

Further, another object of the present invention is to provide amultiple type absorption air conditioning system which automaticallyperforms prevention of crystallization during the cooling operation andcontrol of the flow rate of a cool/warm water so as to eliminate thecooling a room from which no request of a load is made, therebypreventing a waste of energy.

The present invention provides a multiple type absorption airconditioning system which comprises: an absorption cool/warm water unitin which a weak solution diluted by a refrigerant is heated in aregenerator so as to generate refrigerant steam, in which therefrigerant steam is cooled and condensed by a cooling means and is thenevaporated in an evaporator to cool a cool/warm water during a coolingoperation or the refrigerant steam heats the cool/warm water in theevaporator during a heating operation, in which the refrigerant whichhas cooled or heated the cool/warm water in the evaporator is absorbedin or mixed with in an absorber a strong solution produced when therefrigerant steam is generated so as to obtain the weak solution, andthe weak solution is returned to the regenerator; a cool/warm watersystem for introducing the cool/warm water cooled or heated by theabsorption cool/warm water unit; a plurality of water/air heatexchanging means for cooling or heating air by the cool/warm water fromthe cool/warm water system; and an air system for blowing the air cooledor heated by the water air heat exchanging means into individual rooms.

The present invention further provides a multiple type absorption airconditioning system which comprises: an absorption cool/warm water unitin which a weak solution diluted by a refrigerant is heated in aregenerator so as to generate refrigerant steam, in which therefrigerant steam is cooled and condensed by a cooling means and is thenevaporated in an evaporator to cool a cool/warm water during a coolingoperation or the refrigerant steam heats the cool/warm water in theevaporator during a heating operation, in which the refrigerant whichhas cooled or heated the cool/warm water in the evaporator is absorbedin or mixed with in an absorber strong solution produced when therefrigerant steam is generated so as to obtain the weak solution, andthe weak solution is returned to the regenerator; a cool/warm watersystem for introducing the cool/warm water cooled or heated by theabsorption cool/warm water unit; a plurality of water/air heatexchanging means for cooling or heating air by the cool/warm water fromthe cool/warm water system; and an air system for blowing the air cooledor heated by the water air heat exchanging means into individual rooms,wherein further including means for controlling an operation and astoppage of the absorption cool/warm water unit in a cooling or heatingoperation mode, and a switch over of the two operation modes bycontrolling pumps and valves of the absorption cool/warm water unit andof the cool/warm water system, a controller provided in each of thewater air heat exchanging means, the controller having a function ofoperating and stopping the operation of the absorption cool/warm waterunit and a selecting the operation mode of the absorption cool/warmwater unit, and means for transmitting an operation signal from thecontroller to the operation control means so as to allow the absorptioncool/warm water unit to be controlled by the operation of thecontroller.

The cool/warm water system of the air conditioning system according tothe present invention includes a main cool/warm water pipe which comesfrom the absorption cool/warm water unit, a plurality of sub cool/warmwater pipes which lead to a plurality of water air heat exchangingmeans, and branch pipes for connecting the main cool/warm water pipe tothe sub cool/warm water pipes.

In the present invention, since the absorption cool/warm water unitemploys a liquid refrigerant, even when heat input is temporarilystopped when a load is varied, an cooling operation can be continuedwith the residual cooling capacity. It is therefore possible to freelyswitch over the load. Furthermore, the components of an exterior unitwhen the system is activated or when cooling and heating are switchedover are automatically operated by an operation control device, and theoperations of the operation control device can be controlled from acontroller provided at each of the air outlets and connected to theoperation control device via a signal line. Consequently, disability ofthe operation or crystallization of the solution can be eliminated, andthe cooling/heating operation can be provided by a safe and easyoperation conducted in each of the rooms. Furthermore, a multiple typeair conditioning system can be provided in terms of the structure byproviding branching pipes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a system according to thepresent invention;

FIG. 2 is a schematic view of a piping arrangement of the system shownin FIG. 1;

FIG. 3 is a view of a view of a controller of an interior unit;

FIG. 4 is a schematic view of a second embodiment of the presentinvention;

FIG. 5 is a schematic view of a third embodiment of the presentinvention;

FIG. 6 is a schematic view of a fourth embodiment of the presentinvention;

FIG. 7 is a schematic view of a fifth embodiment of the presentinvention;

FIG. 8 is a schematic view of a sixth embodiment of the presentinvention;

FIG. 9 is a schematic view of a seventh embodiment of the presentinvention;

FIG. 10 is a schematic view of an eighth embodiment of the presentinvention; and

FIG. 11 is a schematic view of a ninth embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1, a multiple type absorption air conditioning systemaccording to one embodiment of the present invention includes an outdoorunit or an absorption type cool/warm water unit 30, interior units 31for blowing out the air taken from air inlets 39 through ducts 38 andfilters 37, temperature of which is adjusted by the cool/warm watercoming from the absorption type cool/warm water unit 30 through acool/warm water pipe arrangement 45, and air rate control units (VAVunits) 34 for controlling a flow rate of the air from the interior units31 through ducts 36 and for sending it to ducts 33 and air outlets 32.Each of the interior units 31 is controlled by the respective controller40 provided therein. The flow rate of each of the VAV units 34 isadjusted by controlling the opening degree of a damper (not shown)according to the output of a room thermostat 35.

The cool/warm water pipe arrangement 45 includes a main pipe 45A comingfrom the absorption cool/warm water unit 30, a plurality of sub-pipes45C leading to the interior units 31, and branch pipes 45B connectingthe main pipe 45A to the plurality of subpipes 45C and distributing thecool/warm water. The cool/warm water coming from the single absorptiontype cool/warm water unit 30 is distributed to the individual interiorunits 31, thereby completing a multiple air conditioning system. Each ofthe interior units 31 has the water/air heat exchanging function. Thisis achieved by disposing the sub-pipe 45C in the interior of the duct 38(or in the pipe of the interior unit 31) so as to transmit the heat ofthe cool/warm water in the sub-pipe 45c to the air in the duct 38. Asshown in FIG. 1, the pipe arrangement 45 is a circulation pipearrangement.

The interior unit 31, which is provided on each of the floors, isconnected through the duct 36 to the individual ducts 33 which areprovided in the respective rooms in the floor.

Referring to FIG. 2, the absorption type cool/warm water unit 30includes a high-temperature regenerator 1 for heating absorbed solutionby an external heat source to generate refrigerant steam, alow-temperature regenerator 2, a condenser 3 for cooling the generatedrefrigerant steam by a cooling water to condense it, an evaporator 4 forevaporating the liquid refrigerant by spraying it and for cooling thewater by utilizing the latent heat of evaporation, an absorber 5 formaking the evaporated refrigerant steam absorbed in a solution whilecooling the refrigerant steam, a high-temperature heat exchanger 6 forperforming heat exchange between a strong solution and a weak solution,a low-temperature heat exchanger 7, a pump 9 for circulating solutionand a pump 13 for spraying solution. The absorption type cool/warm waterunit 30 further includes a cooling/heating switch-over valve 18 forallowing the high-temperature refrigerant steam to flow from thehigh-temperature regenerator 1 into the evaporator 4 to heat the warmwater flowing in the pipe, in the heating operation, and a liquidrefrigerant feed control valve 19 for sending out the liquid refrigerantcondensed in the evaporator to the solution system. These valves 18 and19 are operatively connected. A heat source input control device 10 isprovided. Although not shown, an automatic bleeding system (APU) and areservoir tank ST for reserving gas therefor are also provided. In thecooling operation, particularly, in the cooling operation switched overfrom the heating operation, the bleeding system is operated to removevarious types of substances which prohibit absorption. Also, a coolingwater pipe system is provided, which includes a cooling water pipe 21through which a cooling water is supplied into heat-transfer pipes ofthe absorber 5 and of the condenser 3, a cooling tower CT having a fan29, and a pump 22 for pumping cooling water. In the cooling water pipesystem, there are provided a motor driven drain valve 23, an automaticair vent valve 24, a make-up water pipe 25, a motor driven make-up watersupply control valve 26, a float valve 27 and a liquid level switch 28.Three to fifteen interior units 31 are provided, with each of theinterior units 31 including a blower fan 42 and a heat exchanging coil43 through which the cool/warm water flows. The cool/warm water from theevaporator 4 is fed to each of the interior units 31 via a cool/warmwater pipe 45 and an feed forward pipe 47, and back through a returnpipe 46, a cool/warm water pump 50 and the cool/warm pipe 45. A part ofthe cool/warm water flows back to the evaporator 4 through a cool/warmwater bypass pipe 48 which is controlled by a bypass flow rate controlvalve 49. An inlet of the pump 50 is connected to a pipe coming from acistern 51. A cool/warm water flow rate control valve 44 controls theflow rate of the cool/warm water flowing into the interior unit 31.

As shown in FIG. 3, the controller 40 is provided with an operationswitch 60, a cooling operation selection switch 63, a heating operationselection switch 64, a flow rate setting switch 65, a room temperaturesetting switch 66, an operating state display panel 67 and a speaker 68.The controller 40 is connected to an interior unit operation controlpanel 41 via a cross over 61 (FIG. 2).

As shown in FIG. 2, an operation control device 20 is connected to thecontrol panel 41 of the respective interior unit via a signaltransmission line 62. When the switches of any one of the controllers 40are operated, the operation control device 20 receives operation signalsfrom the controller 40 through the corresponding control panel 41. Theoperation control device 20 also receives signals from various types ofdetectors, and performs control of the absorption type cool/warm waterunit 30 and various valves according to the operation signals and thesignals from the detectors. In order to accomplish such an operation,the operation control device 20 is constructed by, for example, amicroprocessor and programs for various operations. First, normalcooling operation will be explained. In the controllers 40 of all theinterior units 31, the cooling operation selection switch 63 isactivated, the flow rate capacity setting switch 65 and the roomtemperature setting switch 66 are operated to set desired flow rate andtemperature. The operation switch 60 is turned on. The signalsrepresenting the operator's demands are sent to the operation controldevice 20 through the interior unit operation panels 41 via the crossover 61 and signal transmission line 62. The cooling/heating switch-overvalve 18 of the absorption type cool/warm water unit 30 is closed, andthe liquid refrigerant feed control valve 19 is also closed. In thatstate, the absorption refrigerating cycle operates in the mannerdescribed below.

In the high-temperature regenerator 1, an absorption solution is heatedby combustion heat of city gas or kerosene to generate refrigerant steamand thereby concentrate the solution. The refrigerant steam generated inthe high-temperature regenerator 1 heats the solution in thelow-temperature regenerator 2 to generate refrigerant steam and therebyfurther concentrate the solution. The refrigerant steam generated in thelow-temperature regenerator 2 and the refrigerant in thehigh-temperature regenerator 1 are led to the condenser 3 where they arecooled by a cooling water and thereby condensed and liquefied. Thecondensed liquid refrigerant is sent to the evaporator 4. The evaporator4 evaporates the liquid refrigerant by spraying to cool the cool/warmwater flowing the pipes by evaporation latent heat. A part of the strongsolution concentrated in the high-temperature regenerator 1 flowsthrough the high-temperature heat exchanger 6 to be mixed with thestrong solution from the low-temperature regenerator 2 and further flowsinto the low-temperature heat exchanger 7. The strong solution from thelow-temperature heat exchanger 7 is sprayed above the pipes in theabsorber 5 by means of the solution spray pump 13. In the absorber 5,the sprayed strong solution is cooled by the cooling water flowingthrough the pipes, while the refrigerant steam from the evaporator 4 isabsorbed into the strong solution to produce a low-temperature weaksolution. The weak solution is fed to the low-temperature heat exchanger7 by the solution circulating pump 8, where heat exchange is performedbetween the strong solution and the weak solution. Behind thelow-temperature heat exchanger 7, the solution is divided into twoportions with one portion being fed to the low-temperature regenerator 2and the other portion being fed to the high-temperature regenerator 1through the high-temperature heat exchanger 6 and the solutioncirculation flow rate control valve 11. The absorption refrigeratingcycle is completed. Lithium bromide aqueous solution is used as thesolution, while water is used as the refrigerant. In the absorber 5 andthe condenser 3, since the gaseous refrigerant is liquefied, if anon-condensed gas is present, the heat-substance moving performancedeteriorates. Hence, the non-condensed gas is extracted from theabsorber 5 and condenser 3 by the automatic bleeding system APU (notshown), and the extracted gas is reserved in the reservoir tank ST (notshown). The automatic bleeding system APU and the reservoir tank STalways operate during the cooling operation.

The water in the cooling tower CT is circulated by means of the coolingwater pump 22. While the cooling water from the cooling tower CT flowsthrough the heat-transfer pipes of the absorber 5 into the heat-transferpipes of the condenser 3, heat exchange is performed. The cooling waterreturns to the cooling tower CT to be sprayed. Air is fed into thecooling tower by the fan 29 to evaporate a part of the cooling water andthereby cool the water. A clean water is supplied into the cooling towerthrough the water supply pipe 25, the control valve 26 and the floatvalve 27 to make up the loss due to evaporation, blowing conducted toprevent concentration of the solid contents, and scatter. To preventidling of the cooling water pump, the liquid level switch 28 isprovided. When it is detected by a cooling water temperature sensor 58that the temperature of the cooling water is lower than a predeterminedvalue, the operation control device 20 stops the fan 29, therebypreventing further reduction in the temperature of the cooling water. Inthis way, the absorption cooling operation can be allowed in a widerange of the atmospheric conditions.

In the cool/warm water system, the cistern 51 is provided to allow thecool/warm water to be present in the pipe arrangement under an adequatepressure. The cool/warm water is led to the group of heat-transfer pipesof the evaporator 4 through the cool/warm water pipe 45 by means of thepump 50. In the evaporator 4, the cool/warm water is cooled by virtue ofthe aforementioned evaporation latent heat of the liquid refrigerant.The cool/warm water thus cooled is fed through the feed forward pipe 47to the individual interior units 31. In the interior unit 31, the cooledcool/warm water is led to the heat exchange coil 43 via the cool/warmwater flow rate control valve 44, where heat exchange is performedbetween the cooled cool/warm water and the air. The cool/warm water fromthe heat exchange coils 43 is collected together to flow through thereturn cool/warm water pipe 46 and then returned to the cool/warm waterpump 50 to complete a circulation. In order to supply the cool/warmwater having a substantially constant temperature to each of theinterior units 31, the operation control device 20 performs outlettemperature control and inlet temperature control. The outlettemperature control is conducted by closing the heat input control valve10 when the temperature detected by the feed forward cool/warm watertemperature detector 53 provided at the outlet of the evaporator 4 isequal to or lower than a predetermined value. The inlet temperaturecontrol is conducted by closing the heat input control valve 10 when thetemperature indicated by the return cool/warm water temperature detector52 is equal to or lower than the predetermined value. The operationcontrol device 20 also controls the bypass flow rate control valve 49 toadjust the bypass flow rate such that the bypass flow rate detected bythe cool/warm water flow rate detector 54 provided in the cool/warmwater pipe 45 becomes equal to a predetermined value when the cool/waterwater flow rate control valve 44 is closed. In the above-mentionedarrangement, the flow rate of the cool/warm water in the evaporator 4can be increased, thus increasing the heat transfer coefficient and,hence, the heat exchange efficiency. Furthermore, since the cool/warmwater can be distributed only to the interior units 31 whose operationsare necessary, energy conservation can be attained.

The outdoor air or the air in the room is suctioned from the air inlet39 through the filter, and then led to the heat exchange coil 43 of theinterior unit 31 through the duct 38. In the heat exchange coil 43, theair is cooled as well as a part of the water contents in the air iscondensed into a drain. The drain is gathered in a drain receiver and isthen discharged to the outside of a building via a drain pipe (notshown). The cooled air is fed through the duct 36, the (VAV) unit 34 andthe duct 33 by means of the blower fan 42 and is then supplied from theoutlet 32 into the room to cool it. The temperature of the air in a roomis detected by the room thermostat 35. When the temperature in the roomis higher than a preset value, the flow rate is increased by opening theVAV unit 34. That is, when the VAV unit 34 is opened, the cool air flowstherethrough more easily, and the pressure detected by an air pressuredetector 74 (not shown) provided in the duct 36 is thus reduced.Therefore, the rotational speed of the blower fan 42 is increased inorder to compensate for the reduced pressure. The rotational speed ofthe fan 42 is varied by motor speed control due to the frequencyconversion by an inverter. This control of the rotational speed isadvantageous in terms of the reduction in the noise level and energyconservation. Furthermore, since the temperature of the indoor air iscontrolled for each room by the room thermostat 35, comfortable airconditioning is available for each room. Furthermore, provision of thesuction duct 38 and blower duct 36 enables the interior unit 31 to bedisposed at the ceiling of a corridor, and thus eliminates provision ofa machine room. Furthermore, since the outdoor air can be taken in fromthe intermediate portion of the suction duct 38 through a filter and ashutter operated by a ventilation operation switch 73 (shown in FIG. 6),the air conditioning quality can be improved. In that case, the outdoorair can be automatically taken in by providing a carbon oxideconcentration detector or an oxygen concentration detector to controlthe opening and closing of the shutter.

The case in which the user gives an instruction to stop the coolingoperation to the controller 40 of one interior unit 31 in the coolingoperation will be described below. In that case, the operation controlpanel 41 of the associated interior unit 31 stops the fan 42 and closesthe cool/warm water flow rate control valve 44 to stop supply of thecool/warm water to the heat exchange coil 43. Consequently, the user canfeel at once that the cooling operation has stopped, and isn'tirritated. Also, heat loss due to natural convection can be reduced, andenergy conservation can thus be accomplished. The operation controldevice 20 closes the heat input control valve 10 of the absorptioncool/warm water unit 30 and thereby temporarily stops heating thehigh-temperature regenerator 1. The heating of the high-temperatureregenerator 1 is returned to its normal mode after a predeterminedperiod of time has elapsed. In this way, rapid reduction in thetemperature of the cool water, which would occur when the relativelylarge load of the interior unit is rapidly eliminated, can be prevented.That is, stoppage of the operation of one interior unit 31 indicatesthat there is the possibility that the operations of the other interiorunits 31 are to be stopped. In case that the interior units 31 receivethe instruction of stopping operation in sequence, the temperature ofthe cool/warm water reduces. Since feeding of the strong solution in thehigh-temperature regenerator 1 and the low-temperature regenerator 2into the absorber 5 is delayed, heat input conducted in that statecauses reduction in the temperature of the cool/warm water andrefrigerant in the evaporator 4 whose heat load has been reduced, thusincreasing the possibility of crystallization and, hence, the safetyoperation may be conducted. The safety operation against the reductionin the temperature of the cool/warm water or refrigerant is to stop theheat input and the solution spraying pump 13 or to open the liquidrefrigerant feed control valve 19. Such safety operation results in aloss of the accumulated heat energy. Thus, temporary stoppage of heatingeliminates the safety operation and thus allows for an energyconservation operation.

When all the interior units 31 receive the instruction for stopping thecooling operation, the operation control device 20 first closes the heatsource control valve 10 of the absorption cool/warm water unit 30 tostop heat input and then opens the refrigerant feed control valve 19 andthe solution bypass valve 12 to blow the liquid refrigerant in theevaporator 4 and to increase the amount of solution circulated to dilutethe solution. When it is detected by the refrigerant level switch 14that the liquid refrigerant in the evaporator 4 has reduced to apredetermined level and when the temperature or pressure of therefrigerant detected by a detector (not shown) in the absorptioncool/warm water unit 30 has thus reached the predetermined value, thecontrol device 20 and the individual control panels 41 in combinationclose the refrigerant feed control valve 19 and the solution bypassvalve 12. Further they stop the fans 42 and close the cool/warm waterunit flow rate control valves 44 of the individual interior units 31.After the bypass flow rate control valve 49 is opened and then the flowrate can be controlled, the refrigerant pump 9, the cool/warm water pump50, the cooling water pump 22, the solution circulating pump 8 and thesolution spraying pump 13 are stopped. Thus, in the case when all theinterior units are to be stopped a stopping of each of the interiorunits 31 is delayed while a load is being applied to the interior unitso as to dilute the solution uniformly. Thus, the controller 40 of theinterior unit 31 can control not only the operation of the interior unit31 but also the operations of the absorption cool/warm water unit 30,the cooling tower CT, the cooling water pump 22 and the cool/warm waterpump 50. Special operation is thus not necessary.

When the operation signal is inputted from the controller 40 of any oneinterior unit 31, the operation control device 20 operates the coolingwater pump 22, the cool/warm water pump 50 and the fan 29 of the coolingtower CT. Also, the corresponding control panel 41 opens the cool/warmwater flow rate control valve 44 of the corresponding interior unit 31and operates the fan 42 to blow air into the room. At that time, it ischecked by the cooling water temperature sensor 58 whether thetemperature of the cooling water is within the predetermined range, itis also checked by the feed forward cool/warm water temperature detector53 or the return cool/warm water temperature detector 52 whether thetemperature and the flow rate of the cool/warm water are predeterminedvalues. When the temperature of the cooling water is low, the fan 29 isstopped. If the temperature of the cooling water doesn't become higherthan a predetermined value after the fan 29 has been stopped, disabilityof the operation is displayed and the system doesn't work. The system isnot operated either when the flow rate of the cool/warm water is lowerthan a predetermined value. When the above-mentioned conditions aresatisfied, the solution circulating pump 8, the refrigerant pump 9 andthe solution spraying pump 13 are operated, and the heat input controlvalve 10 is opened to heat the high-temperature regenerator 1. When thetemperature of the cooling water is low, the solution bypass valve 12 isopened so as to allow the liquid refrigerant to be easily circulated inthe high-temperature regenerator 1. Thus, the cooling operation isactivated by the user's operation instruction alone.

The activation of the cooling operation, the normal operation of thecooling operation and the operation of the system when part or all ofthe interior units are stopped have been described. In either case, thecooling operation can be performed or stopped safely and efficiently bythe user's operation conducted in the room.

When the user turns on the heating selecting switch 64 and the operationswitch 60 of the controller 40 (FIG. 3) of one interior unit 31, thefollowing three cases are possible: (1) the system is in a coolingoperation, (2) the system is in a stop in a cooling operation, and (3)the system is switched over to a heating operation. In the case (1), thecontroller 40 informs the user of disability of switching overacoustically from the speaker 68 using synthetic voice or visually fromthe operation mode display panel 67. Case (3) is the normal heatingoperation and will be described later. Case (2) is a case when thesystem can be switched over to the heating operation. The switching overoperation of case (2) will be conducted in the manner described below.

At that time, the user presses the heating selecting switch 64 on thecontroller 40 of that interior unit 31 a plurality of times within apredetermined period of time. The signals representing a plurality ofpresses are input to the operation control device 20. The operationcontrol device 20 displays the heating operation in the controllers 40of the individual interior units 31. Next, the operation control device20 operates the cool/warm water pump 50, the solution circulating pump 8and the refrigerant pump 9, and opens the heat source control valve 10to heat the high-temperature regenerator 1. Also, the cooling/heatingswitch-over valve 18 and the refrigerant feed control valve 19 areopened so as to allow the liquid refrigerant to be mixed with thesolution and so as to allow the steam generated in the high-temperatureregenerator 1 to flow through the switch-over valve 18 into theevaporator 4. In the evaporator 4, a heat exchange is conducted betweenthe steam and the cool/warm water flowing through the pipes therein andthe steam is condensed. The liquefied refrigerant is fed to the solutionin the absorber 5 by the refrigerant pump 9. During that time, themotor-operated drain valve 23 is opened while the motor-operated watersupply valve 25 is closed. The temperature of the cool/warm water isdetected by the detector 52 or 53. When the cool/warm water temperatureexceeds a predetermined value, the control panel 41 operates the blowerfan 42 of the interior unit 31. The air from through the suction inlet39 and the duct 38 is heated by the heat exchange coil 43, and thensupplied into the room for heating, through the filter 37, the duct 36,the VAV unit 34, the duct 33 and the outlet 32. The air flow rate isvaried according to a result of the comparison between the roomthermostat 35 and the setting temperature set by the switch 66. Thus,the user can comfortably switch over the operation of the airconditioning system from the cooling operation to the heating operationonly by the operation of the controller 40.

In case (3), that is, when the system is in the heating operation, thecooling/heating switch-over valve 18 and the refrigerant feed valve 19are opened, and draining of the cooling water system has been completed.Therefore, when the operation instruction is given, the cool/warm waterpump 50, the solution circulating pump 8 and the refrigerant pump 9 areoperated at once, the heat source control valve 10 is opened to heat thehigh-temperature regenerator 1. Thereafter, the same operation as thatmentioned above is conducted to provide a heating operation.

The operation when the operation mode is switched over from the heatingoperation to the cooling operation will be described below. When acooling signal is output from the controller 40 of one interior unit 31,the following three case are possible: (4) the system is in a heatingoperation, (5) the system is in a stop in a heating operation, and (6)the system is switched over to the cooling operation. In the case of(4), the controller 40 informs the user of disability of switch over.The case (6) is the normal cooling operation and then the aforementionedoperation is conducted. The case (5) is a case when the system can beswitched over from the heating operation to the cooling operation. Inthat case, when the cooling selecting switch 63 of the controller 40 ofthe interior unit 31 is turned on, that the interior unit 31 is set tothe cooling operation mode, however, the remaining interior units 31 arein the heating operation. Hence, similar to the case where the operationis switched over from the cooling operation to the heating operation,the user presses the cooling selecting switch 3 a plurality of timeswithin a predetermined period of time. The signals representing aplurality of presses are inputted to the operation control device 20.The operation control device 20 displays the cooling operation in thecontrollers 40 of the interior units 31. When all the interior unitshave been set in the cooling operation, the operation control device 20closes the motor-operated drain valve 23 and opens the motor-operatedwater supply control valve to supply water to the cooling tower CTthrough the float valve 27. When the water in the cooling tower CT isincreased enough to reach a predetermined level to activate the liquidlevel switch 28, the cooling water pump 22 is operated, and thecooling/heating switch-over valve 18 and the refrigerant feed controlvalve 19 are switched over to the cooling operation, on closed.Thereafter, the cool/warm water pump 50 and the absorption cool/warmwater unit 30 are initiated in sequence, while the non-condensed gas inthe system is exhausted from the reservoir tank ST of the automaticbleeding system APU by a cool water drive aspirator via a cut-off valve,an electromagnetic valve and a check valve. Thus, the cooling operationwhich has been described first in this embodiment can be initiated onlyby the user's operation of the controller, and the safe operation whichis free from freezing of the cool water can thus be performedeffectively without the operation of an expert operator.

In the embodiment of FIG. 1, since the reverse return type pipearrangement is employed in connection with the cool/warm water pipes 46and 47 in the interior units 31, the pressure loss in the cool/warmwater circulating system is made uniform. Therefrom, generation ofvibrations or noises caused by circulation of a large amount ofcool/warm water in the heat exchange coil 43 of the specific interiorunit 31 or erosion of the heat exchange coil 43 caused by after flowingat a high speed can be eliminated.

Another embodiment shown in FIG. 4 differs from that shown in FIG. 1 inthe following points. Namely, the entire amount of the weak solutiongenerated by the absorber 5 is fed through the low-temperature heatexchanger 6 to the high-temperature heat exchanger 6. The weak solutionis fed through the solution circulating rate control valve 11 to thehigh-temperature regenerator 1. After heat exchange is conducted in thehigh-temperature heat exchanger 6 between the strong solution generatedin the high-temperature regenerator 1 and the weak solution, the strongsolution is fed to the low-temperature regenerator 2 by a solution pump13b where it is further concentrated. The strong solution is returnedthrough the low-temperature heat exchanger 7 to the absorber 5 by thesolution spraying pump 13 thereby completing the solution circulation.Further, the difference resides in that the cool/warm pump 50 isdisposed at a position which is beyond the evaporator 4 of theabsorption cool/warm water unit 30. According this, a provision of thesolution bypass valve 12 can be eliminated, and the rotational speed ofthe solution spraying pump 13 and solution pump 13b can be controlled byan inverter due to a change in the solution circulating route. Thisenables the flow rate of the circulating solution to be controlledaccording to the operations. The air system of the embodiment shown inFIG. 4 is the same as that shown in FIG. 1, illustration thereof ispartially omitted.

The embodiment shown in FIG. 5 differs from that shown in FIG. 4 in thefollowing point. Namely, the entire amount of the weak solutiongenerated in the absorber 5 is fed through the low-temperature heatexchanger 7 to the low-temperature regenerator 2 and is heated to becondensed. A part of the condensed solution is fed through thehigh-temperature heat exchanger 6 and the control valve 11 to thehigh-temperature regenerator 1 by means of the pump 13a. After a heatexchange is conducted in the high-temperature heat exchanger 6 betweenthe strong solution generated in the high-temperature regenerator 1 andthe weak solution, the solution is returned to the absorber 5 throughthe low-temperature heat exchanger 7 by the solution spraying pump 13.According this, the cooling operation can be performed under a lowpressure. The air system of the embodiment shown in FIG. 5 is the sameas that shown in FIG. 1, illustration is partially omitted.

The embodiment of FIG. 6 employs an absorption cool/warm water unit 30which is the same as that shown in FIG. 1, the illustration thereof issimplified. The embodiment of FIG. 6 differs from the embodiment shownin FIG. 1 in the following point. Namely, a buffer tank 55 for thecool/warm water is provided while the cool/warm water pipe 45constitutes a circulation passage which connects the evaporator 4 of theabsorption cool/warm water unit 30, the buffer tank 55 and the cool/warmwater pump 50. Furthermore, in the vicinity of the portion of the buffertank 55 in which the cool/warm water cooled by the evaporator 4 flows, asecondary cool/warm water pump 56 is provided. The heat exchanging coils43 of the plurality of interior units 31 and the flow rate controlvalves 44 are connected to the feed forward cool/warm water pipe 47which is, in turn, connected to the discharge side of the pump 56. Thereturn cool/warm water pipe 46 is connected to the portion of the buffertank 55, which portion is close to the cool/warm water pump 50. In thisarrangement, the cool/warm water bypass flow rate control valve 49 canbe eliminated. Instead, the secondary cool/warm water pump 56 can becontrolled by an inverter so as to change the rotational speed thereofand thereby control the flow rate of the cool/warm water. Consequently,energy conservation is achieved. Furthermore, since a constant amount ofcool/warm water can be circulated in the absorption cool/warm water unit30 by the cool/warm water pump 50, it is possible to obtain a heat loadby detecting the temperatures of the cool/warm water at the inlet andthe outlet. This allows for PID control in which the objective value ofthe temperature of the cool/warm water is set and in which the heatinput is controlled on the basis of the objective value and an actualtemperature, and therefore makes the control easy. Furthermore, sincethe buffer tank 55 reduces fluctuations in the temperature of thecool/warm water caused by stoppage of the plurality of interior units 31and fan coil units FC, the control range can be enlarged and comfortablecooling/heating can be offered.

In this embodiment, three types of layout of the interior units 31 andfan coil units FC are disclosed. In the first system (a) a cool/warmwater starts from the feed forward cool/warm water pipe 47, flowsthrough the flow rate control valve 44 and then the heat exchange coil43 of the interior unit 31 and returns to the returning pipe 46(indicated on the left-above in FIG. 6). At that time, the controller 40is installed in each of the rooms provided with the outlet 32, and alsoserves as a controller of the VAV unit 34. The operation signal is sentto the interior unit operation control panel 41 to controlopening/closing of the flow rate control valve 44. The operation signalis also sent to the operation control panel 20 of the absorptioncool/warm water unit system via the cross over 61 and the signaltransmission line 62. In this layout, it is possible to operate theabsorption cool/warm water unit system from an individual room and toprovide air conditioning which suits to each of the rooms.

In a second one is a system (b) a cool/warm water starts from the feedforward cool/warm water pipe 47, passes through the flow rate controlvalve 44, is supplied to a plurality of fan coil units FC connected viabranching pipes and then returns to the returning cool/warm water pipe46 (indicated on the left-middle in FIG. 6). The operation signal ofeach of the fan coil units FC is transmitted to the operation controlpanel 20 through a fan coil unit group centralized control panel 81 viathe cross over 61 by a fan coil unit operation switch 108 so as tooperate the absorption cool/warm water unit system. In this arrangement,it is possible to separately cope with the cooling/heating requests madefrom small rooms. Furthermore, in this system, since a cool/warm wateris supplied, it is possible to eliminate a ventilating device whichwould be required in a conventional cooling/heating multiple systemwhich employs a fluorocarbon gas to prevent an accident of suffocationdue to leakage of a refrigerant. Since the total capacity of the fancoil units FC may be increased to that of the interior unit 31, byincreasing the number of the fan coil units FC, an operation at anextremely small load is not necessary, and smooth operation of theabsorption cool/warm water unit system is ensured.

In a third one is a system (c) a cool/warm water starts from the feedforward cool/warm water pipe 47, passes through the flow rate controlvalve 44 and then the heat exchange coil 43 of the interior unit 31 andthen returns to the returning pipe 46. This system has been describedwith reference to FIG. 1, and description thereof is therefore omitted.

In any of the aforementioned three system (a), (b), (c), since theoperation signal from each of the interior units 31 or each of the fancoil units FC is sent to the operation control panel 20 of theabsorption cool/warm water unit system via the cross over 61 and thesignal transmission line 62, and the heat input is restrictedimmediately after the cooling operation has been stopped, it is possibleto provide an absorption cool/warm water unit system which ensures safeand reliable operation control, which is free from crystallization ofthe solution and which is capable of separately coping with airconditioning requests made in individual rooms.

In FIG. 7, since the embodiment employs an absorption cool/warm waterunit 30 which is the same as that shown in FIG. 6, an illustrationthereof is simplified. The embodiment of FIG. 7 differs from theembodiment of FIG. 1 in the following points. Namely, an end of the feedforward cool/warm water pipe 47 is connected to an end of the returncool/warm water pipe 46, and the cool/warm water branched off from thevicinity of a connecting portion 467 is sent to the evaporator 4 by thecool/warm water pump 50. The evaporator 4 is communicated with the otherend of the pipe 47. Furthermore, when a plurality of secondary cool/warmwater pumps 56a to 56c are not operated, the cool/warm water on whichheat exchange has been subjected in the evaporator 4 passes through thefeed forward cool/warm water pipe 47 and the connecting portion 467 andreturns to the cool/warm water pump 50. In this arrangement, since onlya resistance with which water is passed is applied to the cool/warmwater pump 50, a smaller pump than that use din FIG. 1 can be employed.The secondary pumps can also be made small. Therefore, this embodimenthas an excellent installation property. Furthermore, when an airconditioning request is made from one of the interior units 31, thecool/warm water can be circulated only in the corresponding system byoperating the corresponding secondary cool/warm water pump (for example,56a). Consequently, the flow rate control valve 44 for each of theinterior units 31 can be omitted. Also, since the secondary cool/warmwater pump corresponding to each of the air conditioning requests isoperated, energy conservation can be achieved.

The embodiment of FIG. 8 differs from the embodiment shown in FIG. 1 inthe following points. Namely, a steam pipe which connects thecooling/heating switch-over valve 18 and the evaporator 4 branches intoone portion connected to the bottom portion of a bubble pump 59 and theother portion connected to the evaporator 4. A liquid refrigerantintroducing pipe 78 connected to the bottom portion of the evaporator 4is connected to the bubble pump 59. The discharge portion of the bubblepump 59 is disposed such that the pump 59 can discharge a refrigerantliquid to the absorber 5. When a heating operation instruction is givento the control panel 20 via the signal transmission line 62, thecooling/heating switch-over valve 18 is opened and the bubble pump 59 isdriven by refrigerant steam to discharge the liquid refrigerant in theliquid refrigerant tank at the bottom of the evaporator 4 into theabsorber 5 together with the refrigerant steam. According to theembodiment, of FIG. 8 operation of the refrigerant pump 9 during theheating operation is not necessary, and the required power of the systemcan be reduced. Furthermore, the fan coil unit group centralized panel81 for controlling the plurality of fan coil units FC and the operationswitches 108 thereof is provided in such a manner that it is connectedto the other interior unit control panels 41 via the cross over 61.Consequently, the operation signals from the fan coil units FC are allsent to the fan coil unit group centralized control panel 81 whichtransmits heating/cooling selection signals and the operation signals tothe cool/warm water flow rate control valve 44 from the control panel20. In the embodiment of FIG. 8, since the fan coil unit groupcentralized control panel 81 for integrating the air conditioningrequesting signals from the individual fan coil unit operation switches108 is provided, it is not necessary for excessive signals to be inputto the cross over 61, and the amount of signals can thus be reduced.Consequently, quick control of the entire system is available.

The embodiment of FIG. 9 differs from that shown in FIG. 8 in thefollowing points. Namely, the high-temperature regenerator 1 includes aonce-through boiler type regenerator 80 and a gas-liquid separator 79.According this, the amount of solution reserved can be reduced, and anabsorption cool/warm water unit having a high load responsibility canthus be provided. Furthermore, the low-temperature regenerator 2 is of afull-liquid type which contains the condenser 3 in the upper portionthereof. Since the levels of the solution in the high-temperatureregenerator 1 and the low-temperature regenerator 2 can be made high,the strong solution can be circulated through the absorber 5 by virtueof the liquid head, and then the solution spraying pump 13 can beeliminated. Furthermore, a liquid refrigerant feed valve 19 is disposedfor feeding the liquid refrigerant from the evaporator 4 to the absorber5. In addition to the refrigerant level switch 14, a second liquidrefrigerant level switch 14a is disposed in the liquid refrigerant tankof the evaporator 4 to prevent idling of the refrigerant pump 9. Whenthe cooling operation is stopped, the refrigerant feed valve 19 isopened to discharge the liquid refrigerant from the evaporator 4 to theabsorber 5 dilute the solution until the level of the liquid refrigerantreaches a level detected by the liquid refrigerant level switch 14a. Inthis manner, excessive dilution can be prevented, and the time requiredto start the cooling operation can be shortened. Also, in a case wherethe level of the liquid refrigerant is lower than the level detected bythe liquid refrigerant level switch 14a when the operation is stopped,such dilution of the solution is not conducted, and the solution bypassvalve 12 is opened. Consequently, the very strong solution in thehigh-temperature regenerator 1 can be quickly diluted by the weaksolution and the diluting time can thus be reduced. The air systems inthe embodiments shown in FIGS. 8 and 9 are the same as that shown inFIG. 6, illustration thereof is omitted.

The embodiment of FIG. 10 differs from the embodiment shown in FIG. 9 inthe following points. Namely, the low-temperature regenerator 2 is of aspraying type and the interior units 31 are operated by a remotecontroller RC. Since the low-temperature regenerator 2 is of thespraying type, the amount of strong solution in the low-temperatureregenerator 2 is small, thus reducing the heat capacity thereof.Consequently, an absorption multiple system having an excellent loadresponsibility can be provided. Furthermore, since the remote controllerRC is used for the operation of the interior units, it is not necessaryfor the controller 40 to be disposed on the respective rooms, and layoutof the rooms can be made free.

The embodiment of FIG. 11 differs from the embodiment shown in FIG. 10in the following points. Namely, two absorption cool/warm water units30a and 30b are provided. Two cooling towers CTa and CTb, two coolingwater pumps 22a and 22b, and cool/warm water pumps 50a and 50b areprovided associated with the respective units 30a and 30b. The suctionportions of the cool/warm water pumps 50a and 50b are connected to thereturn cool/warm water pipe 46 so as to allow the cool/warm water toflow through the absorption cool/warm water units 30a and 30b to thefeed forward cool/warm water pipe 47. The feed forward cool/warm waterpipe 47 is provided with a plurality of secondary cool/warm water pumps83 and also with the interior units 31 or a plurality of fan coil unitsFC via the cool/warm water flow rate control valves 44, therebyreturning the cool/warm water to the return cool/warm water pipe 46. Theoperation control panels 41 of the individual interior units 31 areconnected via the cross over 61 to the fan coil unit group centralizedcontrol panel 81, which are in turn connected to a unit number controlpanel 84 and operation control panels 20a and 20b of the absorptioncool/warm water units 30a and 30b via the signal transmission line 62.According to the embodiment of FIG. 11, it is possible to provide alarge-scale air conditioning system by employing the two absorptioncool/warm water units.

In the aforementioned embodiments, the parallel flow type absorptionheater has been described. However, the present invention can alsoapplied to other types of absorption apparatuses, such as series flowtype or reverse flow type. In the series flow type one, the regenerationis conducted on a route of an absorber, a high-temperature regenerator,a low-temperature regenerator and an absorber. In the reverse flow typeabsorber, regeneration is conducted on a route of the absorber, thelow-temperature regenerator, the high-temperature regenerator and theabsorber. The present invention can also be applied to a system whichincludes a single regenerator.

What is claimed is:
 1. A multiple-type air conditioning systemcomprising:an absorption cool/warm water unit in which a weak solutiondiluted by a refrigerant is heated in a regenerator to generaterefrigerant steam, said refrigerant steam is cooled and condensed by acooling means and is then evaporated in an evaporator to cool acool/warm water during a cooling operation, or a cool/warm water isheated by said refrigerant steam in said evaporator during a heatingoperation, the refrigerant from said evaporator is absorbed in or mixedwith a strong solution produced when said refrigerant steam is generatedin an absorber to said weak solution, and said weak solution is returnedto said regenerator; a cool/warm water system through which saidcool/warm water cooled or heated by said absorption cool/warm water unitflows; a plurality of water air heat exchanging means for cooling orheating air by said cool/warm water from said cool/warm water system; aplurality of controllers each provided in the respective water air heatexchanging, said controller having a function of operating and stoppingsaid absorption cool/warm water unit; an integrated controlling meanshaving a function of selecting an operation mode between a cooling modeand a heating mode of said absorption cool/warm water unit; and an airsystem for blowing said air cooled or heated by said water air heatexchanging means into individual rooms.
 2. A multiple-type airconditioning system comprising:an absorption cool/warm water unit inwhich a weak solution diluted by a refrigerant is heated in aregenerator to generate refrigerant steam, said refrigerant steam iscooled and condensed by a cooling means and is then evaporated in anevaporator to cool a cool/warm water during a cooling operation, or acool/warm water is heated by said refrigerant steam in said evaporatorduring a heating operation, the refrigerant from said evaporator isabsorbed in or mixed with a strong solution produced when saidrefrigerant steam is generated in an absorber to said weak solution, andsaid weak solution is returned to said regenerator; a cool/warm watersystem through which said cool/warm water cooled or heated by saidabsorption cool/warm water unit flows; a plurality of water air heatexchanging means for cooling or heating air by said cool/warm water fromsaid cool/warm water system; a plurality of controllers each provided inthe respective water air heat exchanging, said controller having afunction of operating and stopping said absorption cool/warm water unitand of selecting an operation mode between a cooling mode and a heatingmode of said absorption cool/warm water unit; and an integratedcontrolling means having a function of selecting an operation modebetween a cooling mode and a heating mode of said absorption cool/warmwater unit.
 3. A multiple-type air conditioning system comprising:anabsorption cool/warm water unit in which a weak solution diluted by arefrigerant is heated in a regenerator to generate refrigerant steam,said refrigerant steam is cooled and condensed by a cooling means andthen evaporated in an evaporator to cool a cool/warm water during acooling operation, or said cool/warm water is heated by said refrigerantsteam in said evaporator during a heating operation, the refrigerantfrom said evaporator is absorbed in or mixed with a strong solution inan absorber, which is produced when said refrigerant steam is generated,said weak solution, said weak solution is returned to said regenerator;a cool/warm water system through which said cool/warm water cooled orheated in said absorption cool/warm water unit flows; a fan and a heatexchanging coil unit for cooling or heating air by said cool/warm waterfrom said cool/warm water system and for blowing the air cooled orheated by said cool/warm water into individual zones; and a controllerhaving a function of operating and stopping said absorption cool/warmwater unit and of selecting an operation mode between a cooling mode anda heating mode of said absorption cool/warm water unit.
 4. Amultiple-type air conditioning system comprising:an absorption cool/warmwater unit in which a weak solution diluted by a refrigerant is heatedin a regenerator to generate refrigerant steam, said refrigerant steamis cooled and condensed by a cooling means and then evaporated in anevaporator to cool a cool/warm water during a cooling operation, or saidcool/warm water is heated by said refrigerant steam in said evaporatorduring a heating operation, the refrigerant from said evaporator isabsorbed in or mixed with a strong solution in an absorber, which isproduced when the refrigerant steam is generated, to said weak solution,said weak solution is returned to said regenerator; a cool/warm watersystem through which said cool/warm water cooled or heated in saidabsorption cool/warm water unit flows; a plurality of fan and heatexchanging coil units each for cooling or heating air by said cool/warmwater from said cool/warm water system and for blowing the air cooled orheated by said cool/warm water into individual rooms; a plurality ofcontrollers each having a function of operating and stopping saidabsorption cool/warm water unit, said controllers being provided in therespective fan and heat exchanging coil units; and means for selectingan operation mode between a cooling mode and a heating mode of saidabsorption cool/warm water unit.
 5. A multiple-type air conditioningsystem comprising:an absorption cool/warm water unit in which a weaksolution diluted by a refrigerant is heated in a regenerator to generaterefrigerant steam, said refrigerant steam is cooled and condensed by acooling means and then evaporated in an evaporator to cool a cool/warmwater during a cooling operation, or said cool/warm water is heated bysaid refrigerant steam in said evaporator during a heating operation,the refrigerant from said evaporator is absorbed in or mixed with astrong solution in an absorber, which is produced when said refrigerantsteam is generated, to said weak solution, said weak solution isreturned to said regenerator; a cool/warm water system through whichsaid cool/warm water cooled or heated in said absorption cool/warm waterunit flows; a fan and heat exchanging coil unit for cooling or heatingair by said cool/warm water from said cool/warm water system and forblowing the air cooled or heated by said cool/warm water into individualrooms; a plurality of water air heat exchanging means for cooling orheating air by said cool/warm water from said cool/warm water system;and an air system for blowing the air cooled or heated by said water airheat exchanging means into individual rooms.